Some vehicle lighting fixtures can include a light distribution controlling lens configured to control light distribution of light emitted from a light source within a range specified by a desired light distribution standard in order to satisfy such a desired light distribution standard. Furthermore, in order to improve the light utilization efficiency, a configuration illustrated in FIG. 1 is proposed, for example, in Japanese Patent Application Laid-Open No. 2008-078034.
FIG. 1 is a longitudinal cross-sectional view of a vehicle lighting fixture 101 proposed in Japanese Patent Application Laid-Open No. 2008-078034. As illustrated, the vehicle lighting fixture 101 can include an LED 103 serving as a light source and mounted on a flexible substrate 102, and a light distribution controlling lens 104 disposed so that the center thereof is coincident with an optical axis x of the LED 103. The vehicle lighting fixture 101 can further include a cup-shaped light guiding lens 105 around the light distribution controlling lens 104 so that the light guiding lens 105 surrounds the light distribution controlling lens 104. Note that the flexible substrate 102 on which the LED 103 is mounted can be fixed to a heat sink 106 for heat dissipation use.
In the vehicle lighting fixture 101 with the above-described configuration, when the LED 103 is supplied with a current to emit light, the light can enter the light distribution controlling lens 104, and parts L1 and L2 of light rays entering the light distribution controlling lens 104 can be projected through the light emitting surface of the light distribution controlling lens 104 within a range of a desired light distribution standard. The remaining part L3 of light rays, i.e., the light rays emitted by a larger angle with respect to the optical axis x and projected outside the range of the desired light distribution standard in a conventional case, can enter the light guiding lens 105 and travels within the light guiding lens 105 while being repeatedly totally reflected by the same. As a result, the remaining part L3 of light rays can also be projected from the tip end of the light guiding lens 105 within the range of the desired light distribution standard. This means that the conventionally unused light rays L3 can be effectively utilized, so that the light utilization efficiency of light emitted from the LED 103 can be improved.
However, the vehicle lighting fixture 101 proposed in Japanese Patent Application Laid-Open No. 2008-078034 illustrated in FIG. 1 has problems in which the light cannot be projected in a sideward direction (peripheral direction), and the design of the light emitting surface is limited due to the curved light guiding lens 105 (such a curved shape is prerequisite for the light guiding lens 105).